Pharmaceutical M&A got a late-year shot in the arm, with nearly $10 billion in deals being announced involving major industry players like AstraZeneca and Bayer as 2013 came to a close. A bevy of Am Law 100 firms have picked up key advisory roles on the transactions.

Covington & Burling, which represented Salix Pharmaceuticals last month on the company’s $2.6 billion bid for gastrointestinal drug maker Santarus, is now advising AstraZeneca in connection with its agreement to pay up to $4.1 billion to Bristol-Myers Squibb for a stake in an alliance to jointly develop diabetes drugs.